I have been researching a new loudspeaker for some time. Having built hundreds of speakers, designed most of them and ended up not liking them - I had specific requirements that can be summerised as wanting the sound to be natural. Not Hi-Fi (yuk!) not monitor quality (I work in Television and audio is 47% of the experience - SMPTE research figure) not reference quality. Not anything that has an adjective not directly associated with music (i.e. a reference to sound)...

So where did I go to find my ideal sound?

Well, the first speakers I built had a very natural sound but where limited in frequency response - they were small fullrange speakers mounted on open baffles. I loved the ease of there sound - almost like no sound. I have grown to really dislike cross-overs too - horrible things! So I set off searching for the best fullrange loudspeaker and, to cut a long story short, I ended up with the AER speakers - Lowthers done right This led me to BD-Designs in the Netherlands...

And Open Baffles are just so relaxing and natural compared to any box that I had heard. Talking to Bert at BD-Designs - he was just starting to look at an Open Baffle design to complement his Oris horns. So he went his way with his ideas and I followed a parallel course with mine and when I sent my ideas through to him we discovered that we were on the same design path ... Great minds think alike (and fools seldom differ )

Anyway - Bert then refined the design and set of to build mine in Plexiglass - my wife refused a wooden baffle 1.5m by .5m in her house (funny I thought I paid for it ) - and time rolled by...

Bert has delivered the components for my Quasar to me and I still haven't got my plexiglass baffles... What to do? Inspiration struck! I have two large heavy cardboard boxes at home that are about the right size! I'll use them - and so the Cardboard Quasar was born... Hopefully not for long...

Performance wise this speaker is stunning me. I cannot hear the speaker at all - I just hear music. I have tried all types of music and I just hear the instruments and acoustic... so I am very pleased. And my wife will be very pleased when my Plexiglass baffles arrive

- How thick are your baffles going to be (ie thickness of plexi) and will they be clear or coloured? Clear would be very kool.
- How are you crossing the drivers over? Active, passive, biamp, LF compensation?

Though I love my horns, I think a baffle, or another set of Ariels would be all I'd consider again apart from horns. I have a friend who bought some expensive $phile Class A speaks, and then some Fostexes to play with. Three months later, no expensive speakers, and he's working with OB and TL designs. And loving them.
I have a mint set of Goodmans 201's if I ever decide to do a baffle.

Ideally the Plexiglass baffles would be 20mm thick - however they are going to end up 15mm thick for practical reasons... They will, of course, be clear - so as to minimise the visual impact of the speakers

The AER runs full range and the Supervox provides helper support to compensate for baffle loss - it's about 18dB down at 400Hz.

The design can be readily adapted for different speakers but the balancing of the sound is a little tricky as there are several different parameters to tweak. Your Goodmans would be fun to use in an open baffle.

I'm told that in smaller rooms( by Bert) the Quasar is a little fussy to place - However I haven't found it to be position sensitive as long as it's a couple of metres from the nearest wall...

The thing that 'knocks me out' with these speakers is how natural they are. I don't hear the speakers at all. I just hear music. There is no particular sweet spot. In the centre front the sound is a little more focused and as you move away the sound gradulaly blends to mono. Not beamed mono but a consistent sound field that fills the room including behind the speakers. this is true throught the room, actually throughout the house, as long as one is a couple of metres away from the speakers...

This is not to say that the location of sounds within the sound stage is not precise. It is as precise as the original sound field (or so it sounds). It is also very very easy to follow all the different parts of the music.

I also like open baffle speakers. The sound is just "there", even with cheaper drivers. I can't afford a Lowther yet, but I've found that vintage speakers from old consoles can sound very good in open baffle with just a little tweeking. There is a picture of mine on my webpage. Look under hobbies, click on the hifi link.

The bass driver is a Supervox 285GMF. There is a passive filter network to provide baffle step correction via the Supervox coming in under the AER. The filter is about 18dB down at 400Hz. The 215 will need different filter values as it's response it's parameters are quite different from the AER. There is a design for a Supervox open baffle on the Supervox site using these drivers.

The Unopiu chairs are very comfortable and keep my ears at the right height

Hi Jan,

Open Baffles Rock!!! I guess I will investigate a push-pull dipole bass sub to work below the Quasars. It's going to be very difficult to keep the bass note quality the same though... The filter on the Supervox is passive and is an inverse baffle step filter to correct for the limited baffle size and shape. There is also a level matching impedance to match the Supervox sensitivity to the AER. I found the compensation straight-forward - Bert at BD-Designs did it amd he is expert!

The Cardboard works well in this case as it is very non-resonant...It's not terribly pretty though

Hi Dave,

It was my memories of how real, natural and relax that cheap Open Baffle speakers that I made 30 years ago that lead me back to them. Boy am I glad they did!!! I cannot begin to describe how real these speakers are. I've designed a lot of speakers over the years - and been part of design teams developing studio monitors. The Quasars walk all over any other speakers I've heard... I can't beleive it's taken me until I'm 47 to change direction and get it right... Life huh

Nice to see your evolving design - please post your new ideas as they happen.

>It was my memories of how real, natural and relax that cheap Open Baffle speakers that I made 30 years ago that lead me back to them.<

It was my remembering some old consoles I had as a teen that got me looking into open baffles. I had an old Philips console with 10" drivers that had a remarkabe midrange. Voices sounded as good as any I've ever heard. The tubby bass was what spoiled it all. I figured if I get rid of the open backed box which makes a big cavity, I'd get rid of the boom. Worked great! I picked up this old Zenith console at the Salvation Army for $10. Great investment. The 10" drivers have a Fs of 100 Hz, so subs were needed.
I have ordered a pair of old Jensens to try out. They have concentric rings, the Zenith don't. I'm curious to hear the difference, as it could be better yet. Should know in a few days.
Dave

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